In a wireless communications system the transmitted signal is altered by the transmission channel, as well as the receiver processing operations, such as filtering, demodulating, etc. For accurate communications, the receiver must consider these influences in decoding the received data. The receiver determines a relationship between a transmitted signal and a received signal. The relationship may then be applied to subsequent received signals. The relationship may be referred to as a “signature,” wherein the various influences that alter a transmission signal are included in the signature.
Application of the signature to the received signal typically involves complex matrix operations. Various techniques have been developed to simplify the problem by adopting various assumptions. Often these assumptions refer to the noise energy. While some assumptions hold true for transmissions in one type of wireless system, others do not. There is a need therefore for accurate and efficient determination of received signals.